Adjustable Base for Longboard Reverse Kingpin Trucks

ABSTRACT

This invention discloses an adjustable base for skateboard trucks where a two-piece design consisting of a mounting bracket and a slider can be set to any angle within a specific range. The design uses pairs of concentric, mating arced features of different radii on the slider and mounting bracket to maintain constant ride height of the truck assembly when setup with a compatible hanger that has axles which are coincident with the center of the arced features. The design uses a flat on the bottom of the slider to achieve an overall low profile which is desirable to skaters.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT

Not applicable.

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC OR AS A TEXT FILE VIA THE OFFICE ELECTRONIC FILING SYSTEM (EFS-WEB)

Not applicable.

STATEMENT REGARDING PRIOR DISCLOSURES BY THE INVENTOR OR A JOINT INVENTOR

This is a non-provisional utility patent application claiming priority of Jul. 26, 2013 when the related provisional patent application was filed. That provisional patent was application No. 61/859,087.

BACKGROUND OF THE INVENTION

Skateboard trucks are components that are responsible for steering a skateboard as the rider shifts his/her weight away from the center of the deck and towards one of the sides. Every truck is made up of a baseplate that mounts to the skateboard deck and a hanger which houses two axles.

One wheel is mounted on each axle with two bearings in between to reduce rolling resistance. Most hangers also have a pivot and a bushing seat. Two cylindrical urethane bushings are tightened on a kingpin with the bushing seat between them. The kingpin is anchored in the base and a nut is tightened to compress the bushings. The bushings provide resistance against turning.

SUMMARY OF THE INVENTION

The invention is an adjustable base designed to allow the user to change the angle of the axis of rotation of the hanger. The angle of the axis of rotation affects the responsiveness of the truck when the rider leans the board a particular amount. The angle of the axis of rotation is measured between the horizontal and a line drawn from the center of the pivot through the center of the bushing seat. Higher angles result in more turn than lower angles for the same angle of deck tilt.

The adjustable base is a two-piece design comprised of a mounting bracket that fastens directly to the board and a moveable piece, referred to as the “slider,” that can be secured in the mounting bracket. Sets of concentric, mating arced features on the bracket and slider allow constant radial engagement between the pieces. A fastener that goes through both pieces is tightened to prevent the slider from moving once it has been set to a desirable position.

The invention is unique because of the short distance between the axles and the bottom of the base when setup with a compatible hanger. This is accomplished by implementing a flat section in the bottom of the slider and using two or more pairs of concentric, mating arced features.

Another embodiment of the invention is the way the critical faces of the slider are protected by the mounting bracket. Other adjustable bases frequently leave portions of the critical faces on their sliders exposed when set at low angles; this can easily lead to damage caused by impacts with foreign objects which would prevent the base from functioning properly. By fully surrounding the critical faces on the slider with the mounting bracket, impacts with foreign objects while skating are less likely to damage the slider such that it is no longer able to move easily inside of the mounting bracket.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an isometric view of a complete longboard skateboard setup with the adjustable bases.

FIG. 2 is a longboard skateboard with adjustable bases and hangers in a profile view. One wheel is hidden so that two referenced dimensions could be easily shown.

FIG. 3 is a profile view of a longboard with adjustable bases while it is turning.

FIG. 4 is a top view of a longboard with adjustable bases while it is turning.

FIG. 5 is an exploded view of a complete truck using an adjustable base. All hardware and components necessary to secure a hanger to the base are shown.

FIG. 6 is a section view of an adjustable base with kingpin inserted.

FIG. 7 a is a profile view of one adjustable base assembly set at 50 degrees.

FIG. 7 b is an isometric view of one adjustable base assembly set at 50 degrees.

FIG. 8 a is a profile view of one adjustable base assembly set at 35 degrees.

FIG. 8 b is an isometric view of one adjustable base assembly set at 35 degrees.

FIG. 9 is an isometric view of the slider.

FIG. 10 is an isometric view of the mounting bracket.

DETAILED DESCRIPTION

FIG. 1 depicts a longboard setup with adjustable bases and reverse kingpin style hangers. Two adjustable bases 4 are mounted to the deck 1 by way of eight industry standard machine screws 2 using part of the mounting hole pattern 21. The hanger 8 is secured to the base by way of two viscoelastic bushings 7, one above and one below the hanger. A kingpin 14 runs through the base, both bushings and the hanger. Tightening the nut 5 on the kingpin compresses the bushings and provides additional turning resistance. The pivot 11 is inserted into a pivot cup 12 which is housed inside of the slider 13. The slider is secured to the mounting bracket 17 using a machine screw 15 and nut 16 which generates high friction forces between the pieces when tightened. The rider's weight is primarily supported by the radially mating arcs on the mounting bracket and slider.

Angle a1 in FIG. 2 is the axis of rotation of the hanger and it corresponds to the ratio of lean a2 to turn a3 in FIG. 3 and FIG. 4, respectively. At 45 degrees, the ratio of lean-to-turn is 1:1. When a1 is greater than 45 degrees, lean-to-turn is less than 1:1. The opposite is true when a1 is less than 45 degrees: lean-to-turn becomes greater than 1:1.

Skaters are able to change angle a1 by positioning the slider as desired in the mounting bracket and then fastening the machine screw 15. The nut 16 used in conjunction with the machine screw has one flat along its perimeter that is coincident with the horizontal flange on the mounting bracket as shown in FIG. 7 a 22. This prevents the nut from turning as the machine screw is tightened and loosened, which allows the user to use only one tool to make adjustments. The machine screw passes through an arced slot in the slider 19, which acts as a mechanical stop for the maximum and minimum angles that the base is capable of.

FIG. 6 is the cross section of the adjustable base assembly when it is set to an arbitrary angle of 42 degrees. This view shows another critical pair of mating geometry on the slider and mounting bracket 20, this time of a different radius. Additionally, this view also reveals another embodiment of the invention, which is how the critical faces on the slider are surrounded by the mounting bracket at all angle settings a1. This design feature helps protect the dimension-critical faces on the slider 13 from impacts with foreign objects as the skater rides.

The slider has only one degree of freedom when properly seated in the mounting bracket. Concentric pairs of mating geometry between the slider and mounting bracket contribute to this. These pairs are referenced in FIG. 6 20 and FIG. 7 a 23. The center of these arcs 18, 25 is designed to be as close as possible to the center of the axles 9 of a compatible hanger when mounted to the adjustable base. This allows the ride height d1 of the board to remain constant or near constant regardless of what angle the adjustable base is set to, and is also necessary for the separate pairs of arced geometry on the slider and mounting bracket to remain in contact for all possible angle settings of the base.

FIG. 9 and FIG. 10 are isometric views of the slider and mounting bracket, respectively, and are used to the show features on the two pieces which may not have been easily visible in the previous figures. 

1. An adjustable base for skateboard trucks comprised of a mounting bracket that attaches directly to the deck and a slider that can be set at desired angles within the mounting bracket without affecting ride height or wheelbase of the skateboard. The slider is held in place within the bracket by means of one or more machine screws that pass through the bracket. Each machine screw may be pre-tensioned using a compatible nut.
 2. The adjustable base of claim 1 where the slider and mounting bracket have two or more concentric pairs of mating arced features with different radii to provide the slider with radial support from the mounting bracket. The center of the circular arcs coincides with longitudinal axis of the axles of a compatible hanger so that the axle position does not change over the range of the adjustable base.
 3. The adjustable base of claim 2 where a flat along the bottom of the slider is used to reduce the overall height of the assembly when setup in the mounting bracket. 